In recent years, a soldering process with use of a flow soldering bath in production of a printed circuit board has generally been performed by using a mask jig that masks a target with exception of an area to be soldered. Examples of the mask jig include what is called a dip pallet or a carrier pallet. Such a mask jig has required periodic cleaning because accumulation and affixation of flux onto a surface of the mask jig due to repeated use of the mask jig can deteriorate accuracy of the masking.
Under such a circumstance, a cleaning device that cleans an article being cleaned such as a jig onto which flux, an adhesive material, adhesive, or the like is sticking is provided. The cleaning device squirts solvent onto each of the top and bottom surfaces of the article being cleaned in a solvent cleaning tank, thereafter washes out the solvent adhering to the article being cleaned with water, and blows warm air against the article being cleaned for drying.
However, when an article being cleaned onto which flux or the like is sticking is cleaned with a cleaning device that uses solvent, not only usage of a large amount of solvent but also disposal of waste containing the flux or the like and post-cleaning drying can require a large amount of energy as well as a large environmental load. This requires a large cost, which is a problem.
To this end, a cleaning device that causes cleaning media formed of light-weight, easily-airborne solids to be blown in the air at a high velocity in a cleaning tank is provided. The cleaning media are brought into contact with an article being cleaned successively in a cleaning tank so that the cleaning media remove adherents (dusts, powders, filmy dirt sticking onto the article, or the like) from the article being cleaned without using solvent. Because this cleaning device causes the cleaning media to circulate inside the cleaning tank and come into contact with an article being cleaned repeatedly, a great cleaning effect is exerted even when the cleaning device is of a dry type and uses a small amount of the cleaning media. In particular, when the cleaning media are formed of flexible, thin pieces, the cleaning device can attain a level in cleaning effect equal to or better than that of ultrasonic cleaning even with use of a further small amount of the cleaning media.
In the cleaning device described above, an article to be cleaned is placed inside a cleaning tank to receive cleaning media that strike the article to be cleaned. Accordingly, it is required of the cleaning tank to have a capacity equal to or greater than the article to be cleaned.
However, when the cleaning tank is upsized, it becomes difficult to cause the cleaning media to be airborne rather than reside inside the cleaning tank. As a result, the number of times when the cleaning media strike the article being cleaned decreases, and cleaning effect is impaired, which is a problem. This has made it difficult to adapt the cleaning device for cleaning of a large article to be cleaned.
The apparatus disclosed in Patent Document 1 performs cleaning by causing water jet squirted from a nozzle to impinge on an article being cleaned while pressing a leading end of a casing that houses the nozzle therein against the article being cleaned for sealing. Water having been used in cleaning is recovered without leaking to the outside by moving the casing along the article being cleaned.
An apparatus that performs cleaning of a window pane or the like is disclosed in Patent Document 2. A sealing member is arranged to surround a cleaning device body. During cleaning of a window pane, the sealing member is detached from the window pane to define a clearance between the window pane and the sealing member. Air in the clearance is drawn into the cleaning device body and an air stream is generated in the clearance. Cleaning fluid is supplied to the brush in this state to clean the window pane, and the cleaning fluid and cleaned dirt are collected by the air stream.    Patent document 1: Japanese Patent Application Laid-open No. 2004-299042    Patent document 2: Japanese Patent Publication No. S51-25653
However, the cleaning device disclosed in Patent Document 1 is disadvantageous in that, when the cleaning device uses thin-piece cleaning media, the cleaning media can pile up and be caught in a clearance at or near an opening of the cleaning tank like a scaly structure. The caught cleaning media creates a clearance by lifting up a sealing member. This can cause a problem that the cleaning media leak out of a space where the cleaning media are to be blown. When an amount of the cleaning media is undesirably reduced by such leakage, the number of times when the cleaning media strike the article being cleaned decreases, leading to an undesirable result that cleaning effect substantially decreases.
When an article being cleaned by the cleaning device disclosed in Patent Document 2 has an uneven surface, the size of the clearance between the article being cleaned and the sealing member varies due to the uneven surface. Because this variation causes the air stream to become unstable, the cleaning media can leak to the outside. When a cleaning device that causes cleaning media to circulate in the cleaning tank is employed, this leakage of the cleaning media reduces an amount of the cleaning media to be blown in the air. This leads to a problem that the number of times when the cleaning media strike the article being cleaned decreases, and cleaning effect is reduced.
The present invention has been achieved to solve the above circumstances and it is an object of the present invention to provide a cleaning device and a cleaning method capable of effectively cleaning an article being cleaned even when the article being cleaned has a complicated surface profile as well as achieving downsizing of a cleaning tank. This object is attained by positioning the article being cleaned outside the cleaning tank and causing cleaning media to be blown in the air rather than reside inside the cleaning tank.
It is another object of the present invention to prevent leakage of the cleaning media and cause the cleaning media to immediately return to the space where the cleaning media are to be blown so that the number of the cleaning media that strike the article being cleaned is maintained and stable cleaning performance is maintained.